staid

vakaa serious Serious, organized, and professional; sober
1915, w:W. Somerset Maugham|W.S. Maugham, "s:Of Human Bondage/Chapter_CXII|Of Human Bondage":

He wondered what had become of the boys who were his companions: they were nearly thirty now; some would be dead, but others were married and had children; they were soldiers and parsons, doctors, lawyers; they were staid men who were beginning to put youth behind them.